Variable condenser



March 19, 1929.

D. R. DE TAR VARIABLE CONDENSER Filed Dec. 21; 1927 Inventor. Donald RJDQTaT':

His Attchney.

Patented Mar. 19, 192%.

PATENT ortucs.

DQNA'LD it. DE TAR, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEGTRIS UDMIPANY, A GORPQRATION 015 NEW YORK.

VARIABLE CONDENSER. I

Application filed December 21, 1927. Serial No. 241,503.

My invention relates to an electric condenser. More particularly it relates to a condenser of the type especially adapted for use in connection with radio transmission and reception, and to condensers of the type provided with rotor and stator elements.

It is quite common. to construct condensers of the above character with a frame of insulating material, which frame supports both the rotor and stator. ll find, however, that frames of this sort are not altogether satisfactory particularly when-condensers are intended for use in connection with very delicate ad'ustment.

One of the objects of my invention is to provide a condenser of the above character with a metal frame in order to insure that the condenser shall not be perceptibly affected by variations of moisture or temperature in the weather. it is an object of my invention to provide a rigid metal frame and to provide at the points of support for the rotor and stator elements, bushings of in sulating material of minimum spread. 'With this form of construction permanency of electrical characteristic and mechanical rigidity is insured. At the same time it is possible to construct the condenser at a cost equal to or less than that of the type having the objections above indicated.

ihe invention and its objects will be more readily understood from the following specification and claims, reference being had to the accompanying drawing, in which Fig. It shows one form of condenser having the features of my invention. in this figure the condenser is shown in perspective. Fig. 52. is an enlarged section of th condenser of Fig. l in order to more clearly bring out the details of construction. Big. 3 is a section on line 5-3, Fig. 2, viewed in the direction of the arrows, Fig. 2. big. 4. shows a modi fication in the construction of the condenser, the section in Fig. 4 corresponding to the section in Fig. 2. Fi 5 is a section on line 5-5, Fig. 4, Viewed in t 1e direction of the arrows, Fig. 5.

Referring more in detaii to the drawing, it will be seen that the condenser comprises a rotor element 2 mounted on the shaft 3. The condenser is also provided with a stator element 4 clamped in position by three rods 5, 6, 7. The stator and rotor eiements'are sup" ported by a frame consisting of two side plates 8 and? and a base i0, to which the side provided with a flange portion 13 and with a neck or sleeve portion 14. This bushing is removably and adjustably secured to the frame plate 8 by means comprising a hollow stud 15 which receives the sleeve 14 of the bushing. The flange 13 as shown in the draw ing is located between the stud 15 and the drum 16 of the shaft 3. The stud 15 is externally threaded. The plate 8 is provided with a threaded opening for receiving the stud as shown. On the inside of the plate 8 there is provided a lock nut 17 for clamping the stud 15 in position after it has been adjusted with respect to the shaft. By r ring to 1, it will be seen that the opposite plate 9 is provided with a similar bushing, stud and lock nut. @bviously, the friction of the shaft and drum 16 against the bearings can be regulated by means of the stud-elements thus described. The plate 8 is vided with a number of openings through which the rods 5, 6 and Y extend. In each of these openings there is provided a bushing (see for example,"bushings 18, 19 and 20) of insulating material, each molded about its opening as shown in Fig. 3. Each of these bushings is perforated; for example, the bushing 18 is perforated to allow the rod '3 to extend through, the ends of which red are threaded, the portion 21 of which rod. located between the threaded ends, being larger. When the rod is inserted in position as shown in Fig. 3 the bushing 18 is clamped between the section 21 and the lock washer 22 by means of a nut 23. Both ends of the red are of course, identically mounted. The rods 5, 6 and 7 are mounted in exactly the same manner. Obviously, therefore, with the foregoing construction the stator and rotor elements are suitably insulated from each other and from the metal portions of the frame by means of non-metallic bushings insuring a rigid setting for the stator and an edective adjustable support for the rotor.

ltib

in l t and l show a modified form of the device. linstead of having separate bushings for the rotor shaft and for the rod 7 t possible to have a common permanently formed bushing 24: for both the shaft and the rod. Both plates 8 and 9 may be pro ridcd with either form of bushing, or plate 8 may be provided with the form of bushing shown in Fig. 4t and plate 9 with the form of bushing shown in Fig. 3. In order to reinforce the bushing a strip of metal of the plate 8 extends through the insulating material of the bushing, around whichstrip the latter forn'icd.

liliile have disclosed my invention in connection with a specific form of device I do not Wish to be so limited inasmuch as, in View of the disi-lonre, variations may readily be made wiihout departing from the spirit of the invention or from the scope of the claims contained herein.

iihat ll claim as new and desire to secure by Letters Patent of the United States is:

1. An electric condenser having a frame, said frame being provided with side plates, rotor and stator elements mounted in adjustable relation to each other between the saidsidcs, said sides consisting each of a. metal plate with a plurality of bushings of insulatingmaterial, rods for supporting the stator, means for clamping the ends of said rods to said plates, each of said rods extending through one of said bushings of insulating material in each of said sides whereby the rods are insulated from said frame, and a shaft for the rotor, said shaft extending tl'iroug-h one of said bushings in each of said 'sidesfsaid last mentioned bushings serving to insulate said shaft from said sides.

An electric condenser having a frame, said frame being provided with side plates, rotor and stator elements mounted in adjustable relation to each other between the said sides, said sides consisting each of a metal plate with a plurality of bushings of insulating material, rods for supporting the stator, nieans for clamping the ends of said rods to said plates, each of said rods extending throiurh one of said bushings of insulating material in each of said sides whereby the rods are insulated from said frame, and a shaft for the rotor, said shaft extending through one of said bushings in each of said sides. said last mentioned bushings serving to insulate said shaft from said sides, said rotor bushings serving" as bearings for the rotor shaft, said shaft being provided with a slmulder at each end, each shoulder being adjacent one of said bushings, means for adjustingone of said rotor bushings along the rotor shaft to regulate friction between the bushing and the shaft.

3. in electric condenser having a frame, said frame being provided with side plates,

rotor and stator elements mounted in adjustable relation to each other between the said sides, said sides consisting each of a metal plate with a'plurality of bushings of insulating material, rods for supporting the stator, means for clamping the ends of said rods to said plates, each of said rods extending through one of said bushings of insulating material in each of said sides whereby the rods are insulated from said frame, and a shaft for the rotor, said shaft extending through one of said bushings in each of said sides, said last mentioned. bushings serving to insulate said shaft from said sides, said rotor bushings serving as bearings for the rotor shaft, said shaft being provided with a shoulder at each end, each shoulder being adjacent one of said bushings, means for adjusting both of said rotor bushings along the rotor shaft to regulate friction between sai rotor bushings and said rotor shaft.

4. An electric condenser comprising rotor and stator elements, a frame for supporting said elements, said frame comprising a pair of metal plates and a third plate for locking said plates together, said third plate being transverse said first plates, tie rods projecting through said plates, means for locking said tie rods to said plates, a bushing in each plate interposed between each rod and each plate at each point that a rod "passes through each plate, a shaft for the rotor, said shaft also projecting through said plates, a bushing), in each plate interposed between the correspending plate and the shaft, and means for adjusting the shaft bushings, said stator being secured to said rods, said bushings serving to maintain both the stator and rotor insulated from each other and from the frame.

5. An electric condenser comprising rotor and stator elements, a frame for supporting said elements, said frame comprising a pair of metal plates and a. third plate for locking said plates together, said third plate being transverse said'tirst plates, tie rods projecting tl'irough said plates, means for locking, said tie rods to said plates, a bushing in each plate interposed between each rod and each plate at each point that a rod passes through each plate, a shaft for the rotor, said shaft also projecting through said plates, a bushing in each plate interposed between the corresponding plate and the shaft, and means for adjusting the shaft bushings, said means comprising a threaded stud and a lock nut, said stud being in threaded engagement with said frame, said stator being secured to said rods, said bushings serving to maintain both the stator and rotor insulated from each other and from the frame.

In witness whereof. I have hereunto set my hand this 17 day of December, 1927.

DONALD R. DE TAR.

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